/*
* userv service (or standalone program) for per-user IP subranges.
*
- * When invoked appropriately, it creates a point-to-point network
- * interface with specified parameters. It arranges for packets sent out
- * via that interface by the kernel to appear on its own stdout in SLIP or
- * CSLIP encoding, and packets injected into its own stdin to be given to
- * the kernel as if received on that interface. Optionally, additional
- * routes can be set up to arrange for traffic for other address ranges to
- * be routed through the new interface.
- *
* This is the service program, which is invoked as root from userv (or may
* be invoked firectly).
*
*
* The remaining arguments are supplied by the (untrusted) caller:
*
- * <local-addr>,<peer-addr>,<mtu>,<proto>
+ * <local-addr>,<peer-addr>,<mtu>[,[<proto>][,[<ifnamepat>]]]
*
* As for slattach. The only supported protocol is slip.
* Alternatively, set to `debug' to print debugging info and
* not supported). If no additional routes are to be set up, use `-'
* or supply an empty argument.
*
- * Each <config> item - whether a line file such as
- * /etc/userv/ipif-networks, or supplied on the service program
- * command line - is one of:
+ * Each <config> item - whether a line in a file such as
+ * /etc/userv/ipif-networks, or the single trusted argument supplied
+ * on the service program command line - is one of:
*
* /<config-file-name>
* ./<config-file-name>
* service program directly (not via userv), without needing to set up
* permissions in /etc/userv/ipif-networks.
*
+ * Only `*' permits interface name patterns other than the default
+ * value of `userv%d'.
+ *
* #...
*
* Comment. Blank lines are also ignored.
* The service program should be run from userv with no-disconnect-hup.
*/
/*
- * Copyright (C) 1999-2000,2003 Ian Jackson
* This file is part of ipif, part of userv-utils
*
+ * Copyright 1996-2013 Ian Jackson <ijackson@chiark.greenend.org.uk>
+ * Copyright 1998 David Damerell <damerell@chiark.greenend.org.uk>
+ * Copyright 1999,2003
+ * Chancellor Masters and Scholars of the University of Cambridge
+ * Copyright 2010 Tony Finch <fanf@dotat.at>
+ *
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
+ * the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
- * along with userv-utils; if not, write to the Free Software
- * Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
- *
- * $Id$
+ * along with userv-utils; if not, see http://www.gnu.org/licenses/.
*/
#include <stdio.h>
#include <unistd.h>
#include <stdint.h>
#include <poll.h>
+#include <stddef.h>
#include <sys/types.h>
#include <sys/wait.h>
static const unsigned long gidmaxval= (unsigned long)((gid_t)-2);
static const char *const protos_ok[]= { "slip", 0 };
static const int signals[]= { SIGHUP, SIGINT, SIGTERM, 0 };
+static const char default_ifnamepat[]= "userv%d";
static const char *configstr, *proto;
static unsigned long localaddr, peeraddr, mtu;
static int localpming, peerpming;
-static int localallow, peerallow, allallow;
+static int localallow, peerallow, ifnameallow, allallow;
+static char *ifnamepat;
static int nexroutes;
static struct exroute {
unsigned long prefix, mask;
if (len_r) *len_r= len;
}
+static char *eat_optionalstr(const char **argp,
+ const char *what,
+ const char *def) {
+ ptrdiff_t len;
+ const char *start= *argp;
+ if (!start) {
+ len = 0;
+ } else {
+ const char *comma= strchr(start, ',');
+ if (comma) {
+ len= comma - start;
+ *argp= comma + 1;
+ } else {
+ len= strlen(start);
+ *argp= 0;
+ }
+ }
+ if (!len) {
+ start= def;
+ len= strlen(def);
+ }
+ char *r = malloc(len+1);
+ if (!r) sysfatal("malloc for command line string");
+ memcpy(r,start,len);
+ r[len]= 0;
+ return r;
+}
+
static int addrnet_isin(unsigned long prefix, unsigned long mask,
unsigned long mprefix, unsigned long mmask) {
return !(~mask & mmask) && (prefix & mmask) == mprefix;
badusage("failed while reading configuration file: %s", strerror(errno));
cpplace= npp.parent;
+ fclose(file);
}
static void pconfig(const char *configstr, int truncated) {
case '*':
permit_begin();
permit_range(0UL,0UL,1,0);
+ ifnameallow= 1;
return;
case '#':
peeraddr= eat_addr(&carg,"peer-addr", ",",0);
mtu= eat_number(&carg,"mtu", 576,65536, ",",0);
localallow= peerallow= 0;
-
- if (!strcmp(carg,"debug")) {
+
+ char *protostr= eat_optionalstr(&carg,"protocol","slip");
+ if (!strcmp(protostr,"debug")) {
proto= 0;
} else {
for (cprotop= protos_ok;
- (proto= *cprotop) && strcmp(proto,carg);
+ (proto= *cprotop) && strcmp(proto,protostr);
cprotop++);
if (!proto) fatal("invalid protocol");
}
+
+ ifnamepat= eat_optionalstr(&carg,"ifname pattern",default_ifnamepat);
addrnet_mustdiffer("local-addr",localaddr,~0UL, "peer-addr",peeraddr,~0UL);
sprintf(erwhatbuf, "route#%d", i);
checkallow(exroutes[i].allow, erwhatbuf, exroutes[i].prefixtxt, exroutes[i].masktxt);
}
+ if (!strcmp(ifnamepat,default_ifnamepat))
+ ifnameallow= 1;
+ if (!ifnameallow) {
+ fprintf(stderr,
+ "userv-ipif service: access denied for interface name %s\n",
+ ifnamepat);
+ allallow= 0;
+ }
if (!allallow) fatal("access denied");
}
}
static void createif(void) {
- static const char ifnamepat[]= "userv%d";
struct ifreq ifr;
int r;
memset(&ifr,0,sizeof(ifr));
ifr.ifr_flags= IFF_TUN | IFF_NO_PI;
- assert(sizeof(ifr.ifr_name) >= sizeof(ifnamepat));
+ assert(sizeof(ifr.ifr_name) >= strlen(ifnamepat)+1);
strcpy(ifr.ifr_name, ifnamepat);
tunfd= open("/dev/net/tun", O_RDWR);
}
static void rx_packet(const uint8_t *packet, int len) {
+ if (!len)
+ return;
for (;;) {
int r= write(tunfd, packet, len);
if (r<0) {
if (errno==EINTR) continue;
- if (errno==EAGAIN) return; /* oh well */
+ if (errno==EAGAIN || errno==ENOMEM) return; /* oh well */
sysfatal("error writing packet to tun (transmitting)");
}
assert(r==len);
r= read(0, input_buf + input_waiting, want);
if (r>0) {
input_waiting += r;
- assert(r < sizeof(input_buf));
+ assert(input_waiting <= sizeof(input_buf));
more_rx_data(input_buf, rx_packet_buf);
} else if (r==0) {
terminate(0);
~ian / userv-utils.git / blobdiff